1. Field of the Invention
The present invention relates to a method and apparatus for optimizing the cutting of shaped pieces of material from leather, fabric or the like.
2. Description of Related Art
Many different methods are known for cutting out shaped pieces of material. For example, to cut pieces from animal skins, templates may be prepared in accordance with the desired shapes. These templates are placed on the animal skins spread out on the cutting table, and are then manually positioned, taking into consideration all imperfections and other structural features and circumstances pertaining to the leather. The contour or outline of each template is then drawn on the leather and cut out, or the cutting may be effected directly by means of a manual knife which is guided along the template.
Such a method is extremely time-consuming, particularly since smaller templates are very difficult, for ergonomic reasons, to position in the center of an animal skin, which may have dimensions of 3 m.times.3 m. Furthermore the degree of utilization of the leather, i.e., the ratio of the area of the part cut out to the area of the entire animal skin, can be noted only subjectively and is therefore greatly dependent on the experience of the individual who performs the cutting.
Fabrics or other flexurally limp materials can also be cut out in this same way. If patterned material is involved, the process of locating the templates and performing the cutting is made even more difficult by the fact that the template which is spaced on the material conceals the pattern, and aligning the templates to ensure the desired appearance of the subsequent finished piece is very difficult. In this case the degree of utilization is especially low, since the template cannot be repeatedly aligned and outlined on the workpiece, for reasons of cost.
In the case of cutting out three-dimensional non-planar material, the production of the templates is extremely time-consuming and expensive. If the material to be cut furthermore has an irregular three-dimensional shape, it is practically impossible to adjust the placement of the templates. The only way to improve the degree of utilization is to make new templates or to apply the outlines by free-hand drawing.
It is also known to cut leather by means of stamping dies. In this case the knife-sharp stamping dies have the shapes of the pieces which are to be cut out. The dies are applied and positioned, and then corresponding pieces are punched out of the animal skin by applying force to the stamping dies.
In this case the alignment of the dies is similarly problematic. In addition to the weight of the stamping dies, which makes them difficult to handle, damage to the leather by the sharp cutting edges cannot be prevented. The degree of utilization, too, can only be determined subjectively in this method.